I would never recommend the 2A charger we use for anything but shop and battery storage use.

Why wouldn’t you use that maintainer at competition? That’s what we have and it works gloriously.

If you are using batteries faster than that something else is wrong with your competition set up. We use #1-8 our first day, then use the #9-10 the second day before rotating back to #1 and #2. By eliminations we have all 10 batteries topped off again and ready for action.

We haven’t charged a battery over 2 amps in years, and use batteries for 2-3 years before demoting them. We also keep 2-4 old practice batteries for non-match situations.

There are two reasons behind our methods.
One is that the fully sealed 3 bank chargers you can find on AM are very robust, compact, and easy to mount to a battery cart. The battery tenders are not waterproof, need fan cooling and are awkward. We have a custom table built into our build space that house the Battery Tender and nine batteries.
Second is that we dont want to bring ten batteries to every event we go to. Batteries are heavy and team 171 travels in minivans. The lighter we can pack the better.